Inductor component, package component, and switching regulator

ABSTRACT

An inductor component includes a composite body that includes a plurality of composite layers each including a composite material of an inorganic filler and a resin; and a plurality of spiral wires that each are stacked on the composite layer, the spiral wires each being covered with the other composite layer. The average particle diameter of the inorganic filler is equal to or smaller than 5 μm, the wire pitch of the spiral wires is equal to or smaller than 10 μm, and the interlayer pitch between adjacent spiral wires is equal to or smaller than 10 μm.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.15/278,198 filed Sep. 28, 2016, which claims benefit of priority toJapanese Patent Application 2015-197028 filed Oct. 2, 2015, the entirecontent of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an inductor component, a packagecomponent, and a switching regulator.

BACKGROUND

An inductor component described in Japanese Patent Publication No.2013-225718 has traditionally been present. This inductor componentincludes a glass epoxy substrate, spiral wires disposed on both sides ofthe glass epoxy substrate, insulating resins that each cover the spiralwire, and cores that cover the insulating resin thereon andtherebeneath. The core is a metal magnetic powder-including resin andthe core includes metal magnetic powder whose average particle diameteris 20 to 50 μm.

SUMMARY Problems to be Solved by the Disclosure

Electric-power saving techniques are increasingly demanded with theimprovement of the performance of PCs and servers, and the prevalence ofmobile devices. In this situation, an IVR (Integrated Voltage Regulator)technique attracts attention as a technique of reducing the powerconsumption of a CPU (Central Processing Unit).

In a traditional system, as depicted in FIG. 12, a voltage is suppliedfrom a power source 105 to N CPUs 101 in an IC (Integrated Circuit) chip100 through one VR (Voltage Regulator) 103.

On the other hand, in a system employing the IVR technique, as depictedin FIG. 13, an individual VR 113 regulating the voltage from the powersource 105 is disposed for each of the CPUs 101, and the voltagesupplied to the CPU 101 is individually controlled corresponding to theclock operation frequency of the CPU 101.

The supplied voltage needs to be varied at a high speed to control thesupplied voltage to correspond to the variation of the operationfrequency of the CPU 101, and the VR 113 needs a chopper circuit thatexecutes a high speed switching operation at a frequency such as 10 to100 MHz.

Associated with this, a high frequency power inductor is also neededthat can cope with the high speed switching operation at the frequencysuch as 10 to 100 MHz and that can energize at a level of several A as asufficient current to the core during the operation of the CPU 101, asthe inductor used in a ripple filter on the output side of the choppercircuit.

Additionally, the IVR also aims at facilitating downsizingsimultaneously with the electric-power saving by integrating the abovesystem with the IC chip 110, and a small-size high frequency powerinductor capable of being incorporated in the IC package is demanded.Especially, downsizing of the system is advanced by usingthree-dimensional mounting such as SiP (System in Package) or PoP(Package on Package) and, in this situation, a thin-type high frequencypower inductor having a thickness, for example, equal to or smaller than0.33 mm is needed that can be incorporated in an IC package substrate orthat can be mounted on a BGA (Ball Grid Array) side of the substrate.

Because the traditional inductor component has the spiral wires disposedon both of the sides of the glass epoxy substrate, the thickness of theglass epoxy substrate however acts as an obstructive factor and thereduction of the thickness thereof is difficult. The glass epoxysubstrate has the thickness of at least about 80 μm due to the limit ofthe thickness of the glass cloth and the interlayer pitch of the spiralwires in the two layers cannot therefore be reduced any more. When thethickness of this substrate is forcibly reduced, the strength of thesubstrate cannot be maintained, and wire processing and the like becomedifficult.

Because the core includes the metal magnetic powder whose averageparticle diameter is 20 to 50 μm, the size of the metal magnetic powderis large. The thickness of each of the cores on and beneath theinsulating resin is thereby increased and reduction of the thickness isdifficult. For example, to include the metal magnetic powder in theinsulating resin that covers each of the spiral wires to improve theL-value, the wire pitch needs to be secured to be sufficiently largerthan the average particle diameter of the metal magnetic powder anddownsizing is also difficult.

Because the size of the metal magnetic powder is large, the eddy currentloss is large in the metal magnetic powder and, in the high speedswitching operation at a frequency such as 50 MHz to 100 MHz, the lossis large and the high frequency is difficult to be supported.

An object of the present disclosure is to provide an inductor componentthat can support any high frequency and maintains the strength thereofand that can facilitate reduction of the height and downsizing.

Solutions to the Problems

To achieve the object, the inductor component of the present disclosureincludes:

a composite body that includes a plurality of composite layers eachincluding a composite material of an inorganic filler and a resin; and

a plurality of spiral wires that each are stacked on the compositelayer, the spiral wires each being covered with the other compositelayer, wherein

the average particle diameter of the inorganic filler is equal to orsmaller than 5 μm,

the wire pitch of the spiral wires is equal to or smaller than 10 μm,and

the interlayer pitch between adjacent spiral wires is equal to orsmaller than 10 μm.

According to the inductor component of the present disclosure, thespiral wires are each stacked on the composite layer that includes thecomposite material of the inorganic filler and the resin. As to thecomposite layer, any physical defect such as a crack is not generatedtherein even when the composite layer is formed to be a thin film, asufficient strength thereof can be maintained even when the compositelayer is not disposed on a glass epoxy substrate or the like, andreduction of the height can be facilitated by excluding the thickness ofthe glass epoxy substrate.

Because the average particle diameter of the inorganic filler is equalto or smaller than 5 μm, the wire pitch and the interlayer pitch of thespiral wires can be reduced and, because the wire pitch and theinterlayer pitch of the spiral wires are each equal to or smaller than10 μm, reduction of the height and downsizing can be facilitated.

Because the average particle diameter of the inorganic filler is equalto or smaller than 5 μm, when the inorganic filler is a magneticsubstance, the eddy current loss in the magnetic substance is small and,even for a high speed switching operation at a frequency such as 50 MHzto 100 MHz, the loss is small and the high frequency can be supported.

The high frequency can be supported and reduction of the height anddownsizing can be facilitated, maintaining the strength.

In one embodiment of the inductor component, the composite body includesa magnetic composite body whose inorganic filler includes a metalmagnetic material.

According to the embodiment, because the composite body includes themagnetic composite body, even when the inorganic filler is formed to befine particles having the average particle size equal to or smaller than5 μm, high magnetic permeability can be secured and the Q-value of theinductor at a high frequency can be increased.

In one embodiment of the inductor component, the composite body includes

an insulating composite body that covers the spiral wire, the inorganicfiller being an insulating substance; and

the magnetic composite body covers the insulating composite body.

According to the embodiment, because the composite body includes theinsulating composite body and the magnetic composite body, theinsulating composite body improves the insulation between the wires andbetween the layers of the spiral wires and enables further downsizingand reduction of the height or reduction of the resistance of the spiralwires, and the Q-value at the high frequency can be maintained. With themagnetic composite body, a high inductance value can be acquired.

In one embodiment of the inductor component, the inorganic filler of theinsulating composite body is SiO₂ whose average particle diameter isequal to or smaller than 0.5 μm.

According to the embodiment, because the inorganic filler of theinsulating composite body is SiO₂ whose average particle diameter isequal to or smaller than 0.5 μm, the insulation between the wires andbetween the layers of the spiral wires can be enhanced, and downsizingand reduction of the height can further be facilitated.

In one embodiment of the inductor component, the content rate of theinorganic filler in the insulating composite body is equal to or higherthan 20 Vol % and equal to or lower than 70 Vol % relative to theinsulating composite body.

According to the embodiment, because the content rate of the inorganicfiller is equal to or higher than 20 Vol % and equal to or lower than 70Vol %, the fluidity and the linear expansion coefficient of thecomposite body can be set to be adequate, and downsizing and reductionof the height, and improvement of the reliability and the insulation canconcurrently be established.

In one embodiment of the inductor component, the inorganic filler of themagnetic composite body is an FeSi-based alloy, an FeCo-based alloy, anFeNi-based alloy, or an amorphous alloy of these alloys, having theaverage particle diameter that is equal to or smaller than 5 μm.

According to the embodiment, because the inorganic filler of themagnetic composite body is an FeSi-based alloy, an FeCo-based alloy, anFeNi-based alloy, or an amorphous alloy of these alloys, having theaverage particle diameter that is equal to or smaller than 5 μm, theQ-value of the inductor at a high frequency can be increased.

In one embodiment of the inductor component, the content rate of theinorganic filler in the magnetic composite body is equal to or higherthan 20 Vol % and equal to or lower than 70 Vol % relative to themagnetic composite body.

According to the embodiment, because the content rate of the inorganicfiller is equal to or higher than 20 Vol % and equal to or lower than 70Vol %, the fluidity and the linear expansion coefficient are set to beadequate, and downsizing and reduction of the height and highreliability, and a high Q-value at a high frequency can concurrently beestablished.

In one embodiment of the inductor component, the number of turns of theinductor including the spiral wires is equal to or smaller than 10.

According to the embodiment, because the number of turns of the inductorincluding the spiral wires is equal to or smaller than 10, downsizingcan be facilitated securing an L-value necessary during a high speedswitching operation.

In one embodiment of the inductor component, the thickness of acomposite body positioned in an upper portion of the spiral wires in astacking direction and the thickness of a composite body positioned in alower portion of the spiral wires in the stacking direction are equal toeach other and are each equal to or larger than 10 μm and equal to orsmaller than 50 μm.

According to the embodiment, because the thickness of the composite bodyin the upper portion and the thickness of the composite body in thelower portion are equal to each other and are each equal to or largerthan 10 μm and equal to or smaller than 50 μm, the L-value necessary ina high speed switching operation can be acquired with a small thicknessand reduction of the thickness can be facilitated.

In one embodiment of the inductor component, the inductor componentfurther includes a pair of external terminals that are disposed at leastone of over or under the spiral wires in the stacking direction, thepair of external terminals being electrically connected to the spiralwires, and wherein

end faces of the pair of external terminals in the stacking directionare positioned in the same plane as that of an end face of the compositebody in the stacking direction.

The external terminals in this case refer to wires such as Cu wires anddo not include any plating that covers the wires.

According to the embodiment, because the end faces of the pair ofexternal terminals are positioned in the same plane as that of the endface of the composite body, the external terminals do not protrude fromthe end face of the composite body and reduction of the height can befacilitated.

In one embodiment of the inductor component, the pair of externalterminals is buried in the composite body.

According to the embodiment, because the external terminals are buriedin the composite body, downsizing can be facilitated. The externalterminals can be disposed at arbitrary positions on the end face of thecomposite body in the stacking direction and the degree of freedom isincreased for the designing of the layout of the wires and terminals tobe connected.

In one embodiment of the inductor component, one of the pair of externalterminals is disposed both over and under the spiral wires in thestacking direction, and the upper and the lower external terminals areelectrically connected to each other, and the other of the pair ofexternal terminals is disposed at least over the spiral wires in thestacking direction.

According to the embodiment, because the one of the pair of externalterminals is disposed both over and under the spiral wires in thestacking direction, wires conductive for the upper and the lowerexternal terminals can therefore be disposed on the upper and the lowerfaces of the substrate when the inductor component is buried in thesubstrate. The output side of a chopper circuit can be connected in theshortest course by the upper and the lower external terminals that areelectrically connected to each other, without running any more wirearound. The ESR and the ESL of a smoothing capacitor on the output sidecan therefore be reduced and the ripple voltage of the output can bereduced.

In one embodiment of the package component, the package componentincludes:

a substrate; and

the inductor component that is buried in the substrate, wherein

the external terminals on an upper side of the inductor component isdisposed at a side of an upper face of the substrate, and the externalterminal on a lower side of the inductor component is disposed at a sideof a lower face of the substrate, and wherein

wires each electrically connected to the external terminal on the upperside are disposed on the upper face of the substrate and a wireelectrically connected to the external terminal on the lower side isdisposed on the lower face of the substrate.

According to the embodiment, the inductor component is buried in thesubstrate, a wire electrically connected to the external terminal on theupper side is disposed on the upper face of the substrate, and a wireelectrically connected to the external terminal on the lower side isdisposed on the lower face of the substrate. The output side of thechopper circuit can be connected in the shortest course by the upper andthe lower external terminals electrically connected to each other,without running any more wire around. The ESR and the ESL of thesmoothing capacitor on the output side can therefore be reduced and theripple voltage of the output can be reduced.

In one embodiment of a switching regulator, the switching regulatorincludes:

the package component;

a switching element that opens or closes electric connection between anexternal power source and the inductor component; and

a smoothing capacitor that smoothes an output voltage from the inductorcomponent, wherein

the switching element is disposed on a side of the upper face of thesubstrate of the package component, and is electrically connected to thewire connected to the other of the pair of external terminals,

the smoothing capacitor is disposed on a side of the lower face of thesubstrate in the package component and is electrically connected to thewire on the lower side of the wires connected to the one of the pair ofexternal terminals, and

the wire on the upper side of the wires connected to the one of the pairof external terminals is an output terminal.

According to the embodiment, the smoothing capacitor is connected to thewire on the lower face of the substrate of the package component, andthe side of the output terminal connected to a load such as a centralprocessing unit is connected to the wire on the upper face of thesubstrate of the package component similarly to the switching element.The inductor component of the package component, and the load and thesmoothing capacitor can thereby be connected in the shortest courseusing the upper and the lower external terminals, without running anymore wire around. The ESR and the ESL of the smoothing capacitor cantherefore be reduced and the ripple voltage of the output can bereduced.

Effect of the Disclosure

According to the inductor component of the present disclosure, a highfrequency can be supported and reduction of the height and downsizingcan be facilitated, maintaining the strength.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded perspective diagram of a first embodiment of aninductor component of the present disclosure.

FIG. 1B is a cross-sectional diagram of the inductor component.

FIG. 2A is a diagram for explaining a manufacture method of the inductorcomponent.

FIG. 2B is a diagram for explaining the manufacture method of theinductor component.

FIG. 2C is a diagram for explaining the manufacture method of theinductor component.

FIG. 2D is a diagram for explaining the manufacture method of theinductor component.

FIG. 2E is a diagram for explaining the manufacture method of theinductor component.

FIG. 2F is a diagram for explaining the manufacture method of theinductor component.

FIG. 2G is a diagram for explaining the manufacture method of theinductor component.

FIG. 2H is a diagram for explaining the manufacture method of theinductor component.

FIG. 2I is a diagram for explaining the manufacture method of theinductor component.

FIG. 2J is a diagram for explaining the manufacture method of theinductor component.

FIG. 3 is a graph of a frequency property of a composite body to afilling amount of an inorganic filler.

FIG. 4 is a graph of a relation between an inductance value andthicknesses of an upper and a lower magnetic composite bodies.

FIG. 5 is a cross-sectional diagram of a second embodiment of theinductor component of the present disclosure.

FIG. 6A is a diagram for explaining a manufacture method of the inductorcomponent.

FIG. 6B is a diagram for explaining the manufacture method of theinductor component.

FIG. 6C is a diagram for explaining the manufacture method of theinductor component.

FIG. 6D is a diagram for explaining the manufacture method of theinductor component.

FIG. 6E is a diagram for explaining the manufacture method of theinductor component.

FIG. 6F is a diagram for explaining the manufacture method of theinductor component.

FIG. 6G is a diagram for explaining the manufacture method of theinductor component.

FIG. 6H is a diagram for explaining the manufacture method of theinductor component.

FIG. 6I is a diagram for explaining the manufacture method of theinductor component.

FIG. 6J is a diagram for explaining the manufacture method of theinductor component.

FIG. 6K is a diagram for explaining the manufacture method of theinductor component.

FIG. 7 is a cross-sectional diagram of a third embodiment of theinductor component of the present disclosure.

FIG. 8A is a diagram for explaining a manufacture method of the inductorcomponent.

FIG. 8B is a diagram for explaining the manufacture method of theinductor component.

FIG. 8C is a diagram for explaining the manufacture method of theinductor component.

FIG. 9 is a cross-sectional diagram of a first embodiment of a packagecomponent of the present disclosure.

FIG. 10A is a diagram for explaining a manufacture method of the packagecomponent.

FIG. 10B is a diagram for explaining the manufacture method of thepackage component.

FIG. 10C is a diagram for explaining the manufacture method of thepackage component.

FIG. 10D is a diagram for explaining the manufacture method of thepackage component.

FIG. 10E is a diagram for explaining the manufacture method of thepackage component.

FIG. 10F is a diagram for explaining the manufacture method of thepackage component.

FIG. 11A is a cross-sectional diagram of a first embodiment of aswitching regulator of the present disclosure.

FIG. 11B is an equivalent circuit diagram of the switching regulator.

FIG. 12 is a simplified configuration diagram of a traditional system.

FIG. 13 is a simplified configuration diagram of an IVR system.

DETAILED DESCRIPTION

The present disclosure will be described in detail with reference todepicted embodiments.

First Embodiment

FIG. 1A is an exploded perspective diagram of the first embodiment of aninductor component of the present disclosure.

FIG. 1B is a cross-sectional diagram of the inductor component. Thedrawings are schematic, and the relationship among the scales anddimensions of members may be different from the actual relationshipthereamong. As depicted in FIG. 1A and FIG. 1B, the inductor component 1is mounted on an electronic apparatus such as, for example, a personalcomputer, a DVD player, a digital camera, a television, a mobile phone,or automotive electronics.

The inductor component 1 includes two layers of spiral wires 21 and 22,a magnetic composite body 30 (to be an example of a composite body) thatcovers the two layers of spiral wires 21 and 22. “Covering an object”used herein refers to covering at least a portion of the object. In FIG.1A, in the magnetic composite body 30, portions 32 and 33 to have thespiral wires 21 and 22 buried therein are depicted integral with eachother.

The first and the second spiral wires 21 and 22 are sequentiallydisposed from a lower layer to an upper layer. The description will bemade herein assuming that the up-and-down direction of the inductorcomponent 1 matches with the up-and-down direction of the page carryingFIG. 1B thereon. The first and the second spiral wires 21 and 22 areelectrically connected in the stacking direction. The “stackingdirection” refers to a direction for the layers to be stacked and means,for example, a direction along the up-and-down direction of the pagecarrying FIG. 1B thereon. The first and the second spiral wires 21 and22 are each formed in a spiral shape in a plane. The first and thesecond spiral wires 21 and 22 each include a low resistance metal suchas, for example, Cu, Ag, or Au. Preferably, a low-resistance andnarrow-pitch spiral wire can be formed by using Cu plating formed usinga semi-additive process.

External terminals 11 and 12 are disposed above the first and the secondspiral wires 21 and 22 in the stacking direction. The first externalterminal 11 is electrically connected to the first spiral wire 21 andthe second external terminal 12 is electrically connected to the secondspiral wire 22. The external terminals 11 and 12 each include, forexample, the same material as that of the spiral wires 21 and 22. Theexternal terminals 11 and 12 refer to wires such as Cu wires and do notinclude any plating that covers the wires.

The magnetic composite body 30 includes first to fourth composite layers31 to 34. The first to the fourth composite layers 31 to 34 aresequentially disposed from a lower layer to an upper layer. The magneticcomposite body 30 includes a composite material of an inorganic fillerand a resin. The resin is an organic insulating material including, forexample, an epoxy-based resin, bismaleimide, a liquid crystal polymer,polyimide, or the like. The average particle diameter of the inorganicfiller is equal to or smaller than 5 μm. The “average particle diameter”used herein refers to the particle diameter that corresponds to 50% ofthe integrated value in the grain size distribution acquired using alaser diffraction and scattering method. The inorganic filler is amagnetic substance. The inorganic filler is, for example, an FeSi-basedalloy such as FeSiCr, an FeCo-based alloy, an Fe-based alloy such asNiFe, or an amorphous alloy of these alloys, having an average particlediameter that is equal to or smaller than 5 μm. Preferably, the contentrate of the inorganic filler is equal to or higher than 20 Vol % andequal to or lower than 70 Vol % relative to the magnetic composite body30.

The first spiral wire 21 is stacked on the first composite layer 31. Thesecond composite layer 32 is stacked on the first spiral wire 21 andcovers the first spiral wire 21. The second spiral wire 22 is stacked onthe second composite layer 32. The third composite layer 33 is stackedon the second spiral wire 22 and covers the second spiral wire 22. Thefourth composite layer 34 is stacked on the third composite layer 33. Inthis manner, each of the first and the second spiral wires 21 and 22 isstacked on the composite layer and is covered by the other compositelayer that is an upper layer. The magnetic composite body 30 is alsodisposed in an inner diameter portion of each of the first and thesecond spiral wires 21 and 22 that correspond to inner magnetic paths.

The first and the second spiral wires 21 and 22 are disposed centeringthe same one axis. The first spiral wire 21 and the second spiral wire22 are wound in the same one direction, seen from the axis direction(the stacking direction).

The second spiral wire 22 is electrically connected to the first spiralwire 21 through a via wire 27 that extends in the stacking direction.Another via wire 27 is also disposed in the second composite layer 32.An inner circumference part 21 a of the first spiral wire 21 and aninner circumference part 22 a of the second spiral wire 22 areelectrically connected to each other through the via wires 27. The firstspiral wire 21 and the second spiral wire 22 thereby constitute oneinductor.

An outer circumference part 21 b of the first spiral wire 21 and anouter circumference part 22 b of the second spiral wire 22 arepositioned on the sides of both ends of the magnetic composite body 30,seen from the stacking direction. The first external terminal 11 ispositioned on the side of the outer circumference part 21 b of the firstspiral wire 21 and the second external terminal 12 is positioned on theside of the outer circumference part 22 b of the second spiral wire 22.

The outer circumference part 21 b of the first spiral wire 21 iselectrically connected to the first external terminal 11 through the viawire 27 that is disposed in the second composite layer 32, a firstconnection wire 25 that is disposed on the second composite layer 32,and the via wire 27 that is disposed in the third composite layer 33.The outer circumference part 22 b of the second spiral wire 22 iselectrically connected to the second external terminal 12 through thevia wire 27 that is disposed in the third composite layer 33. The outercircumference part 22 b of the second spiral wire 22 is electricallyconnected to a second connection wire 26 that is disposed on the firstcomposite layer 31 through the via wire 27 that is disposed in thesecond composite layer 32.

The thickness in the height direction of each of the first and thesecond spiral wires 21 and 22 is equal to or larger than 40 μm and,preferably, is equal to or smaller than 120 μm. The “height direction”is the direction along the up-and-down direction of the inductorcomponent 1. The wire pitch of each of the first and the second spiralwires 21 and 22 is equal to or smaller than 10 μm and, preferably, isequal to or larger than 3 μm. The interlayer pitch between adjacent thespiral wires 21 and 22 is equal to or smaller than 10 μm and,preferably, is equal to or larger than 3 μm. The wire pitch and theinterlayer pitch are designed values and the manufacture dispersionthereof is about ±20%.

The DC resistance can sufficiently be reduced by setting the wirethickness to be equal to or larger than 40 μm. The wire aspect to be theratio of the thickness in the height direction to that in the widthdirection of the wire is prevented from becoming extremely high bysetting the wire thickness to be equal to or smaller than 120 μm, andany process dispersion can thereby be suppressed. The wire width can betaken to be large by setting the wire pitch to be equal to or smallerthan 10 μm, and the DC resistance can thereby be reliably reduced. Theinsulation between the wires can sufficiently be secured by setting thewire pitch to be equal to or larger than 3 μm. The height can be reducedby setting the interlayer pitch to be equal to or smaller than 10 μm.Any interlayer short-circuiting can be suppressed by setting theinterlayer pitch to be equal to or larger than 3 μm.

The number of turns of the inductor including the first and the secondspiral wires 21 and 22 is equal to or greater than one and equal to orsmaller than 10 and is, preferably, equal to or smaller than 1.5 to 5.In this embodiment, the number of turns is 2.5.

The thickness H1 of the magnetic composite body 30 positioned in theupper portion of the second spiral wire 22 in the stacking direction andthe thickness H2 of the magnetic composite body 30 positioned in thelower portion of the first spiral wire 21 in the stacking direction areequal to each other and are each equal to or larger than 10 μm and equalto or smaller than 50 μm. “Being equal” herein includes beingsubstantially equal in addition to being completely equal.

Upper end faces 11 a and 12 a of the first and the second externalterminals 11 and 12 in the stacking direction are positioned in the sameplane as that of an upper end face 30 a of the magnetic composite body30 in the stacking direction. The first and the second externalterminals 11 and 12 are buried in the magnetic composite body 30. Theupper end faces 11 a and 12 a of the first and the second externalterminals 11 and 12 in the stacking direction may be covered with SnNiplating to improve the solder wettability thereof for the soldermounting.

A manufacture method of the inductor component 1 will be described.

As depicted in FIG. 2A, a base platform 50 is prepared. The baseplatform 50 includes an insulating substrate 51 and base metal layers 52disposed on both faces of the insulating substrate 51. In thisembodiment, the insulating substrate 51 is a glass epoxy substrate andthe base metal layer 52 is a Cu foil sheet. The thickness of the baseplatform 50 does not influence the thickness of the inductor component 1and any base platform 50 having a thickness suitable for easy handlingmay properly be used because of the reasons such as warpage generated inthe processing.

As depicted in FIG. 2B, a dummy metal layer 60 is bonded to one face ofthe base platform 50. In this embodiment, the dummy metal layer 60 is aCu foil sheet. Because the dummy metal layer 60 is bonded to the basemetal layer 52 of the base platform 50, the dummy metal layer 60 isbonded to a smooth face of the base metal layer 52. The adhesive forcebetween the dummy metal layer 60 and the base metal layer 52 cantherefore be weakened and, in the post-process, the base platform 50 cantherefore be easily peeled off from the dummy metal layer 60.Preferably, the adhesive bonding the base platform 50 and the dummymetal layer 60 to each other is a low adhesion adhesive. To weaken theadhesive force between the base platform 50 and the dummy metal layer60, the bonding surface of each of the base platform 50 and the dummymetal layer 60 is advantageously set to be a glossy surface.

The first composite layer 31 is thereafter stacked on the dummy metallayer 60 that is temporarily bonded to the base platform 50. In thiscase, the first composite layer 31 is thermally compressed and thermallycured using a vacuum laminator, a pressing machine, or the like.

As depicted in FIG. 2C, the first spiral wire 21 and the secondconnection wire 26 are stacked on the first composite layer 31. Thefirst spiral wire 21 and the second connection wire 26 are not incontact with each other. The second connection wire 26 is disposed on aside opposite to that of the outer circumference part 21 b. For example,a power supply film for the SAP (Semi Additive Process) is disposed onthe first composite layer 31 using electroless plating, sputtering,vapor deposition, or the like. After disposing the power supply film, aphotosensitive resist is applied or attached to the power supply filmand a wire pattern is formed using photolithography. Metal wirescorresponding to the wires 21 and 22 are thereafter disposed using theSAP. After disposing the metal wires, the photosensitive resist ispeeled and removed using a chemical solution and the power supply filmis removed by etching. Additional Cu electrolytic plating is thereafterapplied using the metal wires as a power supply part, and the wires 21and 22 each having a narrower space can thereby be acquired. In thisembodiment, a Cu wire having L (the wire width)/S (the wire space (thewire pitch))/t (the wire thickness) to be 50/30/60 μm is disposed usingthe SAP and a wire having L/S/t=70/10/70 μm can thereafter be acquiredby executing additional Cu electrolytic plating therefor thatcorresponds to the thickness of 10 μm.

As depicted in FIG. 2D, the second composite layer 32 is stacked on thefirst spiral wire 21 to cover the first spiral wire 21 with the secondcomposite layer 32. The second composite layer 32 is thermallycompressed and thermally cured using a vacuum laminator, a pressingmachine, or the like. In this case, the thickness of the secondcomposite layer 32 above the first spiral wire 21 is set to be equal toor smaller than 10 μm. The interlayer pitch of the first and the secondspiral wires 21 and 22 can thereby be set to be equal to or smaller than10 μm.

To secure the filling into the wire pitch (for example, 10 μm) of thefirst spiral wire 21, the inorganic filler (magnetic substance powder)included in the second composite layer 32 needs to have the particlediameter that is sufficiently smaller than the wire space of the firstspiral wire 21. To realize the reduction of the thickness of thecomponent, the interlayer pitch for the continued wire in the upperportion needs to be reduced to be equal to or smaller than, for example,10 μm and the magnetic substance powder therefore also needs to have aparticle diameter that is sufficiently small.

As depicted in FIG. 2E, via holes to be filled with the via wires 27 aredisposed in the second composite layer 32 using laser processing or thelike. The via holes are thereafter filled with the via wires 27, and thesecond spiral wire 22 and the first connection wire 25 are stacked onthe second composite layer 32. The second spiral wire 22 and the firstconnection wire 25 are not in contact with each other. The firstconnection wire 25 is disposed on a side opposite to that of the outercircumference part 22 b. In this case, the via wires 27, the secondspiral wire 22, and the first connection wire 25 can be disposed usingthe same process as that used for the first spiral wire 21.

As depicted in FIG. 2F, the third composite layer 33 is stacked on thesecond spiral wire 22 to cover the second spiral wire 22 with the thirdcomposite layer 33. The third composite layer 33 is thermally compressedand thermally cured using a vacuum laminator, a pressing machine, or thelike.

As depicted in FIG. 2G, the via holes to be filled with the via wires 27are disposed in the third composite layer 33 using laser processing orthe like. The via holes are thereafter filled with the via wires 27, andthe first and the second external terminals 11 and 12 each having acolumnar shape are stacked on the third composite layer 33. In thiscase, the via wires 27, and the first and the second external terminals11 and 12 can be disposed using the same process as that used for thefirst spiral wire 21.

As depicted in FIG. 2H, the fourth composite layer 34 is stacked on thefirst and the second external terminals 11 and 12 to cover the first andthe second external terminals 11 and 12 with the fourth composite layer34. The fourth composite layer 34 is thermally compressed and thermallycured using a vacuum laminator, a pressing machine, or the like.

The base platform 50 is peeled off from the dummy metal layer 60 in theadhesion surface between the one face of the base platform 50 (the basemetal layer 52) and the dummy metal layer 60. The dummy metal layer 60is removed by etching or the like and, as depicted in FIG. 2I, aninductor substrate 5 is formed.

As depicted in FIG. 2J, the fourth composite layer 34 to be theuppermost layer of the inductor substrate 5 is processed to be a thinfilm using a grinding process. At this time, a portion of each of thefirst and the second external terminals 11 and 12 is exposed and upperend faces 11 a and 12 a of the first and the second external terminals11 and 12 are thereby positioned in the same plane as that of the upperend face 30 a of the magnetic composite body 30. In this case, reductionof the thickness of the component can be facilitated by grinding thefourth composite layer 34 to have a thickness that is sufficient to beable to acquire an inductance value. In this embodiment, the thicknessof the magnetic composite body 30 positioned in the upper portion of thesecond spiral wire 22 in the stacking direction (corresponding to thethickness H1 of FIG. 1B) can be set to be 40 μm.

The inductor substrate 5 is thereafter divided into individual chips bydicing and scribing to form the inductor components 1 each depicted inFIG. 1B. After the division into individual chips, a plating film ofNiSn or the like may be disposed on the first and the second externalterminals 11 and 12 using a method such as barrel plating to enhance themounting property.

Though the inductor substrate 5 is formed on one face of both faces ofthe base platform 50, the inductor substrate 5 may be formed on each ofboth faces of the base platform 50. High productivity can thereby beachieved.

According to the inductor component 1, because the first and the secondspiral wires 21 and 22 are stacked on the composite layer of themagnetic composite body 30, any physical defect such as a crack is notgenerated in the composite layer even when the composite layer is formedto be a thin film, a sufficient strength thereof can be maintained evenwhen the composite layer is not disposed on the glass epoxy substrate orthe like, and reduction of the height can be facilitated by excludingthe thickness of the glass epoxy substrate.

Because the average particle diameter of the inorganic filler of themagnetic composite body 30 is equal to or smaller than 5 μm, the wirepitch and the interlayer pitch of the first and the second spiral wires21 and 22 can be reduced and, because the wire pitch and the interlayerpitch of the first and the second spiral wires 21 and 22 are each equalto or smaller than 10 μm, reduction of the height and downsizing can befacilitated.

Because the average particle diameter of the inorganic filler to be amagnetic substance is equal to or smaller than 5 μm, the eddy currentloss in the magnetic substance is small, the loss is small for a highspeed switching operation at a frequency such as 50 MHz to 100 MHz, andthe support for the high frequency is enabled.

Because the magnetic composite body 30 includes the composite materialof the inorganic filler and the resin, any physical defect such as acrack is not generated therein even when the height thereof is reduced.

The high frequency can be supported, and reduction of the height anddownsizing can be facilitated maintaining the strength.

According to the inductor component 1, because the composite bodyincludes the magnetic composite body 30, high magnetic permeability canbe secured and the Q-value of the inductor at a high frequency can beincreased even when the average particle diameter of the inorganicfiller of the magnetic substance is set to be equal to or smaller than 5μm to be fine particles.

According to the inductor component 1, because the inorganic filler ofthe magnetic composite body 30 is an FeSi-based alloy, an FeCo-basedalloy, or an amorphous alloy of these alloys, having the averageparticle diameter equal to or smaller than 5 μm, the Q-value of theinductor at a high frequency can be increased.

Using an Fe-based material as the inorganic filler provides a highermagnetic moment compared to that of any other soft magnetic materialand, even when the particle diameter is reduced, a relatively highmagnetic permeability can be acquired. The surface of the inorganicfiller may be treated to be insulative using phosphate treatment, silicacoating, or the like to enhance the insulation of the magnetic compositebody 30. The high frequency performance is degraded due to the eddycurrent loss when the insulation of the surface is low.

According to the inductor component 1, because the content rate of theinorganic filler is equal to or higher than 20 Vol % and equal to orlower than 70 Vol %, the fluidity and a high Q-value can concurrently beestablished. FIG. 3 is a graph of a frequency property to a fillingamount (the content rate) of the inorganic filler. FIG. 3 depicts anapproximate straight line acquired when frequencies (MHz) are plottedthat are each acquired when the dielectric tangent (tan δ) is 0.01 witha filling amount (Vol %) of the inorganic filler.

The filling amount (the content rate) is represented by {the volume ofthe inorganic filler/(the volume of the inorganic filler+the volume ofthe resin)}×100. For example, this complies with JIS K 7250 (2006)“Plastic-How to Determine Ash Percentage”. Otherwise, simply, thethree-dimensional dispersion state of the filler is acquired byexecuting SEM observation in the depth direction using an FIB-SEM. Thisdata is the data acquired using an FIB-SEM.

As depicted in FIG. 3, any loss can be suppressed even for a high speedswitching operation at an operation frequency of 10 MHz and the propertycan be maintained even at a high frequency by setting the content rateof the inorganic filler to be equal to or lower than 70 Vol %. Thecontent rate of the inorganic filler is, preferably, equal to or lowerthan 65 Vol % and, especially, is, more preferably, equal to lower than60 Vol %. From FIG. 3, any loss can be suppressed for a high speedswitching operation at a frequency up to 50 MHz when the content rate isequal to or lower than 65 Vol % and up to 100 MHz when the content rateis equal to or lower than 60 Vol %, and the property can be maintainedat a high frequency.

Preferably, the content rate of the inorganic filler is equal to higherthan 20 Vol % and, in this case, the fluidity and the linear expansioncoefficient of the composite body can adequately be secured and acomposite body can be acquired whose downsizing, height reduction, andreliability improvement can be facilitated.

According to the inductor component 1, because the number of turns ofthe inductor including the first and the second spiral wires 21 and 22is equal to or smaller than 10, downsizing can be facilitated securingthe L-value necessary for a high speed switching operation.

According to the inductor component 1, because the thickness H1 of themagnetic composite body 30 in the upper portion and the thickness H2 ofthe magnetic composite body 30 in the lower portion are equal to eachother and are each equal to or larger than 10 μm and equal to or smallerthan 50 μm, the L-value necessary for a high speed switching operationcan be acquired with a small thickness and reduction of the thicknesscan be facilitated.

FIG. 4 depicts the relation between the inductance value (the L-value)and the thicknesses of the magnetic composite bodies on and beneath thespiral wires, for each number of the turns of the spiral wires. FIG. 4depicts the values measured using an electromagnetic field simulationconcerning the magnetic composite body that satisfies the conditions ofthis application. A solid line therein represents the case of 2.5 turnsand a dotted line therein represents the case of 4.5 turns. As depictedin FIG. 4, because the L-value saturates against the thickness,reduction of the height of the component can be facilitated securing theL-value necessary for a high speed switching operation by setting thethicknesses of the magnetic composite bodies thereon and therebeneath toeach be equal to or smaller than 50 μm.

According to the inductor component 1, because the upper end faces 11 aand 12 a of the first and the second external terminals 11 and 12 arepositioned in the same plane as that of the upper end face 30 a of themagnetic composite body 30, the first and the second external terminals11 and 12 do not protrude from the upper end face 30 a of the magneticcomposite body 30 and reduction of the height can be facilitated.

According to the inductor component 1, because the first and the secondexternal terminals 11 and 12 are buried in the magnetic composite body30, downsizing can be facilitated.

Example 1

An Example of the first embodiment will be described. The inductorcomponent is a power inductor that is used in a step-down switchingregulator for a switching frequency of 100 MHz and that has the size of1 mm×0.5 mm and the thickness of 0.23 mm. The number of turns of theinductor including the spiral wires is 2.5 in the two-layer structure,and the inductance value thereof is about 5 nH at 100 MHz.

The number of turns of each of the spiral wires is set to be able toacquire the necessary inductance value matching with the switchingfrequency. The number of turns is set to be equal to or smaller than 5for a switching frequency of 50 MHz to 100 MHz.

The spiral wire has the size of L/S/t=70/10/70 μm, and L and t are setcorresponding to the chip size and the allowable current to be energizedto the inductor. The interlayer pitch of the spiral wires is 10 μm thatis equal to the wire pitch, and the spiral wires can densely be woundand downsizing and reduction of the height of the inductor are enabledby setting the pitch between the wires and the interlayer pitch of thespiral wires to be equal to or smaller than 10 μm to be significantlynarrow.

Second Embodiment

FIG. 5 is a cross-sectional diagram of the second embodiment of theinductor component of the present disclosure. The second embodiment isdifferent from the first embodiment only in the configuration of thecomposite body. Only the different configuration will be described. Inthe second embodiment, the same reference numerals as those of the firstembodiment denote the same configurations as those of the firstembodiment and will not again be described.

As depicted in FIG. 5, the composite body of an inductor component 1Aincludes an insulating composite body 40 that covers the first and asecond spiral wires 21 and 22, and a magnetic composite body 30A thatcovers the insulating composite body 40. The material of the magneticcomposite body 30A is the same as the material of the magnetic compositebody 30 of the first embodiment.

The insulating composite body 40 includes the composite material of theinorganic filler and the resin. The resin is an organic insulatingmaterial including, for example, an epoxy-based resin, bismaleimide, aliquid crystal polymer, polyimide, or the like. The average particlediameter of the inorganic filler is equal to or smaller than 5 μm. Theinorganic filler is an insulating substance such as SiO₂. Preferably,the inorganic filler is SiO₂ having the average particle diameter equalto or smaller than 0.5 μm. Preferably, the content rate of the inorganicfiller is equal to or higher than 20 Vol % and equal to or lower than 70Vol % relative to the insulating composite body 40.

The insulating composite body 40 includes a hole 40 a at the positioncorresponding to the inner diameter portion of each of the first and thesecond spiral wires 21 and 22. The magnetic composite body 30A isdisposed in the hole 40 a of the insulating composite body 40 thatcorresponds to the inner magnetic path, and on and beneath theinsulating composite body 40 that corresponds to the outer magneticpaths.

The insulating composite body 40 includes first to third compositelayers 41 to 43. The first to the third composite layers 41 to 43 aresequentially disposed from a lower layer to an upper layer. The firstspiral wire 21 is stacked on the first composite layer 41. The secondcomposite layer 42 is stacked on the first spiral wire 21 to cover thefirst spiral wire 21. The second spiral wire 22 is stacked on the secondcomposite layer 42. The third composite layer 43 is stacked on thespiral wire 22 to cover the second spiral wire 22.

The upper end faces 11 a and 12 a of the first and the second externalterminals 11 and 12 are positioned in the same plane as that of theupper end face 30 a of the magnetic composite body 30A. The first andthe second external terminals 11 and 12 are buried in the magneticcomposite body 30A.

A manufacture method of the inductor component 1A will be described.

As depicted in FIG. 6A, the base platform 50 is prepared. The baseplatform 50 includes the insulating substrate 51 and the base metallayers 52 disposed on both sides of the insulating substrate 51. In thisembodiment, the insulating substrate 51 is a glass epoxy substrate andthe base metal layer 52 is a Cu foil sheet. The thickness of the baseplatform 50 does not influence the thickness of the inductor component1A and any base platform 50 having a thickness suitable for easyhandling may properly be used because of the reasons such as warpagegenerated in the processing.

As depicted in FIG. 6B, the dummy metal layer 60 is bonded to the oneface of the base platform 50. In this embodiment, because the dummymetal layer 60 is a Cu foil sheet. Because the dummy metal layer 60 isbonded to the base metal layer 52 of the base platform 50, the dummymetal layer 60 is bonded to the smooth face of the base metal layer 52.The adhesive force between the dummy metal layer 60 and the base metallayer 52 can therefore be weakened and, in the post-process, the baseplatform can be easily peeled off from the dummy metal layer 60.Preferably, the adhesive bonding the base platform 50 and the dummymetal layer 60 to each other is a low adhesion adhesive. To weaken theadhesive force between the base platform 50 and the dummy metal layer60, the bonding surface of each of the base platform 50 and the dummymetal layer 60 is advantageously a glossy surface.

The first composite layer 41 is thereafter stacked on the dummy metallayer 60 that is temporarily bonded to the base platform 50. At thistime, the first composite layer 41 is thermally compressed and thermallycured using a vacuum laminator, a pressing machine, or the like. Aportion of the first composite layer 41 corresponding to the innermagnetic path (the magnetic core) is thereafter removed using a laser orthe like to dispose an opening 41 a.

As depicted in FIG. 6C, the first spiral wire 21 and the secondconnection wire 26 are stacked on the first composite layer 41. Thefirst spiral wire 21 and the second connection wire 26 are not incontact with each other. The second connection wire 26 is disposed on aside opposite to that of the outer circumference part 21 b. For example,a power supply film for the SAP (Semi Additive Process) is disposed onthe first composite layer 41 using electroless plating, sputtering,vapor deposition, or the like. After disposing the power supply film, aphotosensitive resist is applied or attached to the power supply filmand the wire pattern is formed using photolithography. The metal wirescorresponding to the wires 21 and 22 are thereafter disposed using theSAP. After disposing the metal wires, the photosensitive resist ispeeled and removed using a chemical solution and the power supply filmis removed by etching. Additional Cu electrolytic plating is thereafterapplied using the metal wires as a power supply part, and the wires 21and 22 each having a narrower space can thereby be acquired. A firstsacrifice conductor 71 corresponding to the inner magnetic path isdisposed on the dummy metal layer 60 in the opening 41 a of the firstcomposite layer 41. The first sacrifice conductor 71 is disposed usingthe SAP. In this embodiment, the Cu wire having L (the wire width)/S(the wire space (the wire pitch))/t (the wire thickness) to be 50/30/60μm is disposed using the SAP and a wire having L/S/t=75/5/73 μm canthereafter be acquired by executing additional Cu electrolytic platingtherefor that corresponds to the thickness of 12.5 μm.

As depicted in FIG. 6D, the second composite layer 42 is stacked on thefirst spiral wire 21 to cover the first spiral wire 21 with the secondcomposite layer 42. The second composite layer 42 is thermallycompressed and thermally cured using a vacuum laminator, a pressingmachine, or the like. At this time, the thickness of the secondcomposite layer 42 above the first spiral wire 21 is set to be equal toor smaller than 5 μm. The interlayer pitch of the first and the secondspiral wires 21 and 22 can thereby be set to be equal to or smaller than5 μm.

To secure the filling property into the wire pitch (for example, 5 μm)of the first spiral wire 21, the inorganic filler (the insulatingsubstance) included in the second composite layer needs to have theparticle diameter that is sufficiently smaller than the wire pitch ofthe first spiral wire 21. To realize the reduction of the thickness ofthe component, the interlayer pitch for the continued wire in the upperportion needs to be reduced to be equal to or smaller than, for example,5 μm, and the insulating substance therefore needs to also have aparticle diameter that is sufficiently small.

As depicted in FIG. 6E, via holes 42 b to be filled with the via wires27 are disposed in the second composite layer 42 using laser processingor the like. A portion of the second composite layer 42 corresponding tothe inner magnetic path (the magnetic core) is removed using a laser orthe like and an opening 42 a is disposed.

As depicted in FIG. 6F, the via holes are filled with the via wires 27and the second spiral wire 22 and the first connection wire 25 arestacked on the second composite layer 42. The second spiral wire 22 andthe first connection wire 25 are not in contact with each other. Thefirst connection wire 25 is disposed on a side opposite to that of theouter circumference part 22 b. At this time, the second spiral wire 22is disposed using the same process as that for the first spiral wire 21.A second sacrifice conductor 72 corresponding to the inner magnetic pathis disposed on the first sacrifice conductor 71 in the opening 42 a ofthe second composite layer 42. At this time, the via wires 27, thesecond spiral wire 22, the first connection wire 25, and the secondsacrifice conductor 72 can be disposed using the same process as thatfor the first spiral wire 21.

As depicted in FIG. 6G, the third composite layer 43 is stacked on thesecond spiral wire 22 to cover the second spiral wire 22 with the thirdcomposite layer 43. The third composite layer 43 is thermally compressedand thermally cured using a vacuum laminator, a pressing machine, or thelike.

As depicted in FIG. 6H, a portion of the third composite layer 43corresponding to the inner magnetic path (the magnetic core) is removedusing a laser or the like to dispose an opening 43 a.

The base platform 50 is thereafter peeled off from the dummy metal layer60 in the adhesion surface between the one face of the base platform 50(the base metal layer 52) and the dummy metal layer 60. The dummy metallayer 60 is removed by etching or the like, the first and the secondsacrifice conductors 71 and 72 are removed by etching or the like, and,as depicted in FIG. 6I, a hole 40 a corresponding to the inner magneticpath is disposed in the insulating composite body 40. Via holes 43 b tobe filled with the via wires 27 are thereafter disposed in the thirdcomposite layer 43 using laser processing or the like. The via holes 43b are filled with the via wires 27, and the first and the secondexternal terminals 11 and 12 each having a columnar shape are stacked onthe third composite layer 43. At this time, the via wires 27, and thefirst and the second external terminals 11 and 12 can be disposed usingthe same process as that for the first spiral wire 21.

As depicted in FIG. 6J, the first and the second external terminals 11and 12, and the insulating composite body 40 are covered with themagnetic composite body 30A, and an inductor substrate 5A is therebyformed. The magnetic composite body 30A is thermally compressed andthermally cured using a vacuum laminator, a pressing machine, or thelike. The magnetic composite body 30A also fills the hole 40 a of theinsulating composite body 40.

As depicted in FIG. 6K, the magnetic composite body 30A on and beneaththe inductor substrate 5A is processed to be a thin film using agrinding process. At this time, a portion of each of the first and thesecond external terminals 11 and 12 is exposed and upper end faces 11 aand 12 a of the first and the second external terminals 11 and 12 arethereby positioned in the same plane as that of the upper end face 30 aof the magnetic composite body 30A. In this case, reduction of thethickness of the component can be facilitated by grinding the magneticcomposite body 30A to have a thickness that is sufficient to be able toacquire an inductance value. For example, in this embodiment, thethickness thereof can be set to be 35 μm.

The inductor substrate 5A is thereafter divided into individual chips bydicing and scribing to form the inductor components 1A each depicted inFIG. 5. After the division into individual chips, a plating film of NiSnor the like may be applied to the first and the second externalterminals 11 and 12 using a method such as barrel plating to enhance themounting property thereof.

Though the inductor substrate 5A is disposed on one face of both facesof the base platform 50, the inductor substrate 5A may be disposed oneach of both faces of the base platform 50. High productivity canthereby be achieved.

According to the inductor component 1A, because the composite bodyincludes the insulating composite body 40 and the magnetic compositebody 30A, the insulation between the wires and the interlayer insulationof the first and the second spiral wires 21 and 22 can be secured by theinsulating composite body 40, and a high inductance value can beacquired due to the magnetic composite body 30A.

According to the inductor component 1A, the inorganic filler of theinsulating composite body 40 is SiO₂ having the average particlediameter equal to or smaller than 0.5 μm, the insulation between thewires and the interlayer insulation of the first and the second spiralwires 21 and 22 can therefore be enhanced, and downsizing and reductionof the height can further be facilitated. Compared to the firstembodiment, the insulation between the wires and the interlayerinsulation can further be enhanced by employing the insulating substanceas the inorganic filler, and the wire pitch of the first and the secondspiral wires 21 and 22, and the interlayer pitch can therefore bereduced.

According to the inductor component 1A, because the content rate of theinorganic filler of the insulating composite body 40 is equal to orhigher than 20 Vol % and equal to or lower than 70 Vol %, the fluidityand the insulation can concurrently be established.

Example 2

An Example of the second embodiment will be described. The inductorcomponent is a power inductor that is used as a use thereof in astep-down switching regulator for a switching frequency of 100 MHz andthat has the size of 1 mm×0.5 mm and the thickness of 0.23 mm. Thenumber of turns of each of the spiral wires is 2.5 in the two-layerstructure, and the inductance value thereof is about 5 nH at 100 MHz.

The number of turns of each of the spiral wires is set to be able toacquire the necessary inductance value matching with the switchingfrequency. The number of turns is set to be equal to or smaller than 10for a switching frequency of 40 MHz to 100 MHz.

Though the Example is depicted that includes the spiral wire whose L/S/tis L/S/t=75/5/73 μm, L and t are set corresponding to the chip size andthe allowable current to be energized to the inductor. The interlayerpitch of the spiral wires is 5 μm that is equal to the wire pitch, andthe spiral wires can densely be wound and downsizing and reduction ofthe height of the inductor are enabled by setting the wire pitch and theinterlayer pitch of the spiral wires to be equal to or smaller than 10μm to significantly be narrow.

Third Embodiment

FIG. 7 is a cross-sectional diagram of the third embodiment of theinductor component of the present disclosure. The third embodiment isdifferent from the second embodiment only in the quantity of theexternal terminals, and copes with incorporation thereof into a packagesubstrate. Only the different configuration will be described. In thethird embodiment, the same reference numerals as those of the secondembodiment denote the same configurations as those of the secondembodiment and will not again be described.

As depicted in FIG. 7, in an inductor component 1B, the externalterminals 11 to 14 are disposed both over and under the first and thesecond spiral wires 21 and 22 in the stacking direction. The inductorcomponent 1B includes the third and the fourth external terminals 13 and14 in addition to the first and the second external terminals 11 and 12of the second embodiment.

The third and the fourth external terminals 13 and 14 are disposed underthe first and the second spiral wires 21 and 22 in the stackingdirection. The third external terminal 13 faces the first externalterminal 11 and is electrically connected to the first external terminal11 through the via wire 27. The fourth external terminal 14 faces thesecond external terminal 12 and is electrically connected to the secondexternal terminal 12 through the via wire 27.

Lower end faces 13 a and 14 a of the third and the fourth externalterminals 13 and 14 in the stacking direction are positioned in the sameplane as that of a lower end face 30 b of the magnetic composite body30A in the stacking direction. The third and the fourth externalterminals 13 and 14 are buried in the magnetic composite body 30A.

A manufacture method of the inductor component 1B will be described.

A method is executed that is the same as the method depicted in FIG. 6Ato FIG. 6H of the second embodiment.

As depicted in FIG. 8A, the hole 40 a corresponding to the innermagnetic path is disposed in the insulating composite body 40. The viaholes 43 b in the upper and the lower face of the insulating compositebody 40 are filled with the via wires 27. The first and the secondexternal terminals 11 and 12 each having a columnar shape are disposedon the upper face of the third composite layer 43, and the third and thefourth external terminals 13 and 14 each having a columnar shape aredisposed on the lower face of the first composite layer 41. In thiscase, the via wires 27 and the first, the second, the third, and thefourth external terminals 11, 12, 13, and 14 can be disposed using thesame process as that for the first spiral wire 21.

As depicted in FIG. 8B, the first to the fourth external terminals 11 to14 and the insulating composite body 40 are covered with the magneticcomposite body 30A and the inductor substrate 5B is thereby formed. Themagnetic composite body 30A is thermally compressed and thermally curedusing a vacuum laminator, a pressing machine, or the like. The hole 40 aof the insulating composite body 40 is also filled with the magneticcomposite body 30A.

As depicted in FIG. 8C, the magnetic composite body 30A on and under theinductor substrate 5B is processed to be a thin film using a grindingprocess. In this case, a portion of each of the first to the fourthexternal terminals 11 to 14 is exposed, the upper end faces 11 a and 12a of the first and the second external terminals 11 and 12 are therebypositioned in the same plane as that of the upper end face 30 a of themagnetic composite body 30A, and the lower end faces 13 a and 14 a ofthe third and the fourth external terminals 13 and 14 are therebypositioned in the same plane as that of the lower end face 30 b of themagnetic composite body 30A. In this case, reduction of the thickness ofthe component can be facilitated by grinding the magnetic composite body30 to have a thickness that is sufficient to be able to acquire aninductance value.

The inductor substrate 5B is thereafter divided into individual chips bydicing and scribing to form the inductor components 1B each depicted inFIG. 7. After the division into individual chips, a plating film of NiSnor the like may be applied to the first and the second externalterminals 11 and 12 using a method such as barrel plating to enhance themounting property thereof.

Though the inductor substrate 5B is formed on one face of both faces ofthe base platform 50, the inductor substrate 5B may be formed on each ofboth faces of the base platform 50. High productivity can thereby beachieved.

According to the inductor component 1B, because the external terminals11 to 14 are disposed both over and under the spiral wires 11 and 12 inthe stacking direction, wires conductive for the external terminals 11to 14 on and beneath the inductor component 1B can be disposed on theupper and the lower faces of the substrate when the inductor component1B is buried in the substrate. The output side of the chopper circuitbranched into two directions that are the side to connect the load andthe ground side through the smoothing capacitor can therefore beconnected to each other in the shortest course without running any morewire around, by the upper and the lower external terminals that areelectrically connected to each other. The ESR and the ESL of thesmoothing capacitor on the output side can therefore be reduced and theripple voltage of the output can be reduced.

Because the two terminals are used only for the external terminals onthe output side as above, the external terminal on the input side may beone and, for example, either the external terminal 13 or 14 does notneed to be disposed in the inductor component 1B. Disposing both of theexternal terminals 13 and 14 can however improve the symmetry in theinductor component 1B, and can facilitate reduction of asymmetry of theproperty, improvement of the degree of freedom of wiring, improvement ofco-planarity of the overall component, and the like.

Example 3

An Example of the third embodiment will be described. The inductorcomponent is a power inductor that is used as a use thereof in astep-down switching regulator for a switching frequency of 100 MHz andthat has the size of 1 mm×0.5 mm and the thickness of 0.23 mm. Thenumber of turns of each of the spiral wires is 2.5 in the two-layerstructure, and the inductance value thereof is about 5 nH at 100 MHz.

Fourth Embodiment

FIG. 9 is a cross-sectional diagram of one embodiment of the packagecomponent of the present disclosure. In the fourth embodiment, the samereference numerals as those of the third embodiment denote the sameconfigurations as those of the third embodiment and will not again bedescribed.

As depicted in FIG. 9, the package component 2 is a module that includesa substrate in an IC package and includes the substrate 80 and theinductor component 1B of the third embodiment that is buried in thesubstrate 80. The substrate 80 includes, for example, FR4, CES3, or thelike. The first and the second external terminals 11 and 12 on the upperside of the inductor component 1B are disposed on the side of an upperface 80 a of the substrate 80. The third and the fourth externalterminals 13 and 14 on the lower side of the inductor component 1B aredisposed on the side of a lower face 80 b of the substrate 80.

Wires 81 and 82 are disposed on the upper face 80 a of the substrate 80through an insulating resin 85. The first wire 81 is electricallyconnected to the first external terminal 11 through an opening of theinsulating resin 85. The second wire 82 is electrically connected to thesecond external terminal 12 through an opening of the insulating resin85.

Wires 83 and 84 are disposed on the lower face 80 b of the substrate 80through the insulating resin 85. The third wire 83 is electricallyconnected to the third external terminal 13 through an opening of theinsulating resin 85. The fourth wire 84 is not electrically connected toany of the external terminals 11 to 14.

A manufacture method of the package component 2 will be described.

As depicted in FIG. 10A, the substrate 80 is prepared. For example, athin substrate having a thickness of 0.33 mm, 0.23 mm, or the like isused as the substrate 80 for downsizing and reduction of the height ofthe IC.

As depicted in FIG. 10B, a penetrating hole 80 c is disposed in thesubstrate 80 using a drill, a laser, or the like.

As depicted in FIG. 10C, a temporary attachment tape 86 with lowadhesion is attached to the lower face 80 b of the substrate 80. Athermally foamed sheet or the like may be used instead of the temporaryattachment tape 86.

As depicted in FIG. 10D, the inductor component 1B is installed in thepenetrating hole 80 c. The insulating resin 85 such as a build-up sheet,a pre-preg, or the like is thereafter laminated on the upper face 80 aof the substrate 80, the inductor component 1B and the substrate 80 aresealed, and the temporary attachment tape 86 is removed.

As depicted in FIG. 10E, the insulating resin 85 is laminated on thelower face 80 b of the substrate 80, the insulating resins 85 arethereafter thermally cured, and the substrate 80 having the inductorcomponent 1B buried therein is acquired.

As depicted in FIG. 10F, via holes are disposed using a laser in theportions of the insulating resins 85 to be contact points between theexternal terminals 11 to 13 of the inductor component 1B and thecircuit. In this case, because the surface of the magnetic compositebody 30A and the surfaces of the external terminals 11 to 13 aredisposed on the same smooth plane, defective processing due toout-of-focus laser processing and the like tend to be avoided and theproductivity can be improved. The smear caused by the laser isthereafter removed and wiring layers 87 are disposed using an approachsuch as electroless plating or electrolytic plating.

Etching processing is applied to the wiring layers 87 using resistpatterns and the like to dispose the necessary lands and wires on thesubstrate 80 and, as depicted in FIG. 9, the package component 2 can beacquired.

According to the package component 2, the inductor component 1B isburied in the substrate 80, the wires 81 and 82 electrically connectedto the external terminals 11 and 12 on the upper side are disposed onthe upper face 80 a of the substrate 80, and the wire 83 electricallyconnected to the external terminal 13 on the lower side is disposed onthe lower face 80 b of the substrate 80. The output side of the choppercircuit can be connected in the shortest course without running any morewire around using the external terminals 11 and 13 on the upper and thelower sides electrically connected to each other. The ESR and the ESL ofthe smoothing capacitor on the output side can therefore be reduced andthe ripple voltage of the output can be reduced.

Fifth Embodiment

FIG. 11A is a cross-sectional diagram of one embodiment of a switchingregulator of the present disclosure. FIG. 11B is an equivalent circuitdiagram of the switching regulator. In the fifth embodiment, the samereference numerals as those of the fourth embodiment denote the sameconfigurations as those of the fourth embodiment and will not again bedescribed.

As depicted in FIG. 11A and FIG. 11B, the switching regulator 3 playsthe role of a voltage regulator (VR) that converts a power sourcevoltage from an external power source (not depicted) into a voltagesuitable for a central processing unit 121 and that supplies theconverted voltage to the central processing unit 121.

The switching regulator 3 includes the package component 2 of the fourthembodiment, a switching element 123 a that opens or closes the electricconnection between the external power source and the inductor component1B, and a smoothing capacitor 90 that smoothes the output voltage fromthe inductor component 1B.

The switching element 123 a is disposed on the side of the upper face 80a of the substrate 80 of the package component 2 and is electricallyconnected to the second wire 82 connected to the external terminal 12 ofthe other (on the input side) of the pair (on the input and the outputsides) of external terminals. The smoothing capacitor 90 is disposed onthe side of the lower face 80 b of the substrate 80 of the packagecomponent 2 and is electrically connected to the wire 83 on the lowerside of the wires 81 and 83 connected to the external terminals 11 and13 of the one (on the output side) of the pair (on the input and theoutput sides) of external terminals. The wire 81 on the upper side isthe output terminal, of the wires 81 and 83 connected to the externalterminals 11 and 13 of the one (on the output side) of the pair (on theinput and the output sides) of external terminals.

A voltage regulating part 123 and the central processing unit 121 areintegrated in one IC chip 120. The IC chip 120 is mounted on the upperface 80 a of the substrate 80 of the package component 2. The voltageregulating part 123 includes the switching element 123 a and a driver123 b that drives the switching element 123 a. The switching element 123a is connected to the second wire 82 of the package component 2 throughan internal connection electrode 91. The central processing unit 121 isconnected to the first wire 81 of the package component 2 through theinternal connection electrode 91.

The smoothing capacitor 90 is mounted on the lower face 80 b of thesubstrate 80 of the package component 2. An input part of the smoothingcapacitor 90 is connected to the third wire 83 of the package component2. An output part of the smoothing capacitor 90 is connected to thefourth wire 84 of the package component 2. The fourth wire 84 isconnected to the ground through an external connection electrode 92.

As above, the switching element 123 a is connected to the input part ofthe inductor component 1B, and the central processing unit 121 and thesmoothing capacitor 90 are connected to the output part of the inductorcomponent 1B. Though not depicted, the IC chip 120 and the substrate 80are integrated with each other by a molded-in epoxy resin or the like toconstitute one single IC package.

According to the switching regulator 3, the smoothing capacitor 90 isconnected to the wires 83 and 84 on the lower face 80 b of the substrate80 of the package component 2, and the switching element 123 a and thecentral processing unit 121 are connected to the wires 81 and 82 on theupper face 80 a of the substrate 80 of the package component 2. Theinductor component 1B of the package component 2, and the centralprocessing unit 121 and the smoothing capacitor 90 can thereby beconnected to each other in the shortest course without running any morewire around, by the first and the third external terminals 11 and 13 inthe upper and the lower portions. The ESR and the ESL of the smoothingcapacitor 90 can therefore be reduced and the ripple voltage of theoutput can be reduced. A load other than the central processing unit 121may be connected to the first wire 81 to be the output terminal.

The present disclosure is not limited to the embodiments and theirdesigns can be changed within the scope not departing from the gist ofthe present disclosure. For example, the features of each of the firstto the fifth embodiments may variously be combined with each other.Though the inductor component includes the spiral wires in the twolayers in the embodiments, the inductor component may include spiralwires in three or more layers.

Though the number of inductors including the spiral wires is one in theembodiments, the number of inductors included in the inductor componentis not limited to one. For example, spiral wires having plural spiralsin one same plane may configure plural inductors.

1. An inductor component comprising: a composite body that includes acomposite material including an inorganic filler and a resin, thecomposite body having an upper end face and a lower end face, the lowerend face being provided on a surface of the composite body opposite tothe upper end face; a wire that is disposed inside the composite body,the wire being disposed in a plane parallel to the upper or the lowerend face; a first external terminal that is disposed in the upper endface of the composite body; a second external terminal that is disposedin the upper end face of the composite body; and a third externalterminal that is disposed in the lower end face of the composite body,wherein a first end part of the wire is electrically connected to boththe first external terminal and the third external terminal, and asecond end part of the wire is electrically connected to only the secondexternal terminal.
 2. The inductor component according to claim 1,wherein the wire is formed in a spiral shape in the plane parallel tothe upper or the lower end face.
 3. The inductor component according toclaim 1, wherein a number of turns of an inductor including the wire isequal to or smaller than
 10. 4. The inductor component according toclaim 1, further comprising a plurality of wires disposed inside thecomposite body and forming a spiral shape along the plane parallel tothe upper or the lower end face.
 5. The inductor component according toclaim 4, wherein a wire pitch of the wires is equal to or smaller than10 μm.
 6. The inductor component according to claim 4, wherein aninterlayer pitch between adjacent wires is equal to or smaller than 10μm.
 7. The inductor component according to claim 1, wherein an averageparticle diameter of the inorganic filler is equal to or smaller than 5μm.
 8. The inductor component according to claim 7, wherein theinorganic filler is SiO₂ with an average particle diameter equal to orsmaller than 0.5 μm.
 9. The inductor component according to claim 7,wherein the inorganic filler is an FeSi-based alloy, an FeCo-basedalloy, an FeNi-based alloy, or an amorphous alloy of these alloys 10.The inductor component according to claim 7, wherein a content rate ofthe inorganic filler is equal to or higher than 20 Vol % and equal to orlower than 70 Vol % relative to the composite body.
 11. The inductorcomponent according to claim 1, wherein a thickness of the compositebody positioned in an upper portion of the wire in a stacking directionand a thickness of the composite body positioned in a lower portion ofthe wire in the stacking direction are equal to each other.
 12. Theinductor component according to claim 11, wherein the thickness of thecomposite body positioned in an upper portion of the wire in a stackingdirection and the thickness of the composite body positioned in a lowerportion of the wire in the stacking direction are each equal to orlarger than 10 μm and equal to or smaller than 50 μm.
 13. The inductorcomponent according to claim 1, wherein each of the external terminalsis buried in the composite body.
 14. A package component comprising: asubstrate; and the inductor component according to claim 1 that isburied in the substrate, wherein a wire electrically connected to thefirst external terminal and a wire electrically connected to the secondexternal terminal are disposed on an upper surface of the substrate, anda wire electrically connected to the third external terminal is disposedon a lower surface of the substrate.
 15. A switching regulatorcomprising: the package component according to claim 14; a switchingelement that opens or closes electric connection between an externalpower source and the inductor component; and a smoothing capacitor thatsmoothes an output voltage from the inductor component, wherein theswitching element is disposed on the upper surface of the substrate ofthe package component and is electrically connected to the wireconnected to the second external terminal, the smoothing capacitor isdisposed on the lower surface of the substrate of the package componentand is electrically connected to the wire connected to the thirdexternal terminal, and the wire connected to the first external terminalis an output terminal.